Different Concentrations Of Substance Research Articles

Utilisation of titanium-containing wastes in the cement industry: A literature review

The metallurgical industry is among the leaders in waste production which has a high potential for recycling. The review paper considers the problems of metallurgical industry waste management and some possible ways of their solution. Waste acidic pickling solutions of titanium (titanium sludge) can be used as an additive to cement clinkers both to improve the characteristics of building materials and the efficiency of their production process. The influence of calcium fluoride (CaF2) and titanium dioxide (TiO2) on cement clinkers at different concentrations of substances and sintering temperatures has been reviewed. The data on changes in the content of free lime (f-CaO), patterns of formation and distribution of clinker phases: alite, belite, celite and calcium aluminiferite have been presented. Mechanisms of CaF2 and TiO2 inclusion in the composition of various cement phases have been explained. The conclusion has been made that the application of titanium-containing wastes allows not only to recycle them, but also to obtain construction materials with improved characteristics.

Comparing the Anti-candidal Effect of Egg White (Machine and Local) with Amphotericin B in Vitro

Introduction: The increase in the resistance of fungal species and the high side effects of antifungal drugs have led researchers to study and find new treatment methods against fungi. This study evaluated the anti-candidacy effects of local and artificial egg whites and compared them with amphotericin B. Materials and Methods: This study was conducted experimentally in May 2023 in the Microbiology Laboratory of Khalkhal Faculty of Medical Sciences. This research tested the antifungal effects of local and machine chicken egg whites and amphotericin B using the micro broth dilution and zone of inhibition method. In this experiment, Candida albicans species were placed in the vicinity of different concentrations of substances, and the minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) of these substances on C. albicans were determined according to the guidelines of the Clinical and Laboratory Standards Institute. This study has been registered with the ethical code IR. IR.KHALUMS.REC.1401.019 in the Ethics Committee of Khalkhal Faculty of Medical Sciences. Results: Based on the results of the tests, the MIC of local and machine chicken egg whites on C. albicans was 25%, and their MFC was 50%. However, in these concentrations, no growth was observed in the presence of amphotericin B. Moreover, the MIC and MFC values of 25 µl of amphotericin B with 75 µl of local and machine egg whites were 3.125% and 6.25%, respectively. The zone of inhibition for C. albicans in the vicinity of local and machine chicken egg white and amphotericin B was 12, 11, and 16 mm, respectively. Conclusion: Local and machine chicken egg whites have antifungal properties against C. albicans.

Effect of Polystyrene Microplastics on the Antioxidant System and Immune Response in GIFT (Oreochromis niloticus).

Recent studies have revealed a significant presence of microplastics (MPs) in freshwater ecosystems, raising concerns about their potential negative impacts on the growth and development of freshwater organisms. The present study was conducted to examine the effects of chronic sub-lethal doses of polystyrene microsphere MPs on the oxidative status (ROS, SOD) and the immune response (IL-1ß, TNF-α) of genetically improved farmed tilapia (a kind of tilapia hereafter referred to as GIFT). GIFT juveniles (5.1 ± 0.2 g) were exposed to different concentrations of substances. The experimental groups were as follows: group A (control, no exposure), group B (exposed to a concentration of 75 nm), group C (exposed to a concentration of 7.5 μm), group D (exposed to a concentration of 750 μm), group E (exposed to a combination of 75 nm, 7.5 μm, and 750 μm), and group F (exposed to a combination of 75 nm and Chlorella). The ROS contents in the brain and gills were significantly decreased in group F, while a significant increase was observed in group D following a 14-day exposure. SOD activities in the intestine showed an elevation in group F, as did those in the brain and gills in group D, while the SOD levels in the gills generally decreased over time in groups B and F. Notably, the highest ROS and SOD were observed in the brain of group D, whereas the lowest were in the intestines at the same concentration. The activity of IL-1β in the liver was significantly up-regulated in all of the exposure groups. IL-1β was significantly up-regulated in the brain of group B and in the gills of group D. Similarly, TNF-α was significantly up-regulated in the brain of groups B/D/E, in the liver of groups B/C/D, in the intestine of group B, and in the gills of group D. Notably, the highest levels of IL-1β and TNF-α activities were recorded in the brain, while the lowest were recorded in the intestine of group D. Overall, this study revealed that GIFT's immune response and antioxidant system can be affected by MPs.

Substance P is overexpressed in cervical squamous cell carcinoma and promoted proliferation and invasion of cervical cancer cells in vitro.

This study aimed to investigate the expression and function of substance P in cervical squamous cell carcinoma. Cancer tissues and adjacent tissues of 20 patients with cervical squamous cell carcinoma in our hospital were collected. The expression of substance P was detected by immunohistochemistry and Western blot analysis. Cervical squamous cell carcinoma line SiHa was treated with different concentrations of substance P. The proliferation of SiHa cells was detected by EdU assay, and the invasion ability of SiHa cells was detected by transwell assay. The phosphorylation of ERK1/2 and the expression of MMP9 were detected by Western blot analysis. The results showed that substance P was expressed in the cytoplasm and some cell membranes of cervical squamous cell carcinoma cells. The expression of substance P in cervical cancer tissues was significantly higher than that in the adjacent tissues. Compared with the control group, substance P significantly promoted the proliferation and invasion of SiHa cells in a concentration dependent manner and activated the phosphorylation of ERK1/2 and upregulated the expression of MMP9 in SiHa cells. In conclusion, substance P is highly expressed in cervical squamous cell carcinoma and can promote cervical cancer cell proliferation and invasion. The mechanism is related to the activation of ERK1/2 pathway to upregulate MMP9.

Reliable numerical analysis for stochastic reaction-diffusion system

In this article, stochastic behavior of reaction diffusion brusselator model is under consideration. There are many physical phenomena which are related to chemical concentrations. One chemical concentration coincide with the other chemical concentration and their inter-diffusion is a major question to be addressed and to be understood. So, that is why Brusselator model is very proto-type and standard model that lays the foundation of any kind of that matter chemical concentrations of different substances. It also has the application in physical species as well. That is why we are considering such model. The existence of solution is guaranteed with fix-point operator, self mapping and pre-compact conditions. Nonstandard finite difference scheme and Crank-Nicolson schemes are used to show the graphical behavior of the model. The consistency and stability of the schemes are discussed and both schemes are unconditionally stable. The 3D and 2D graphs represents the concentration of the models.

Electric Cell-Substrate Impedance Sensing (ECIS) as a Convenient Tool to Assess the Potential of Low Molecular Fraction Derived from Medicinal Fungus Cerrena unicolor in Action on L929 and CT-26 Cell Lines.

The increase in the incidence of cancer has contributed to the search for new therapeutic methods. In recent years, the use of preparations of natural origin from medical fungi has increased. One such active substance is the extracellular, low molecular active fraction obtained from the medicinal fungus Cerrena unicolor. This study aimed to monitor the pharmacokinetics of different concentrations of substances isolated from the medicinal fungus Cerrena unicolor (ex-LMS) using the ECIS technique. In the study, mouse L929 fibroblasts and colon cancer CT26 cell lines were treated with different concentrations of the active fractions obtained from Cerrena unicolor: C1 = 2.285 (μg/mL); C2 = 22.85 (μg/mL); and C3 = 228.5 (μg/mL). This study demonstrated that the tested preparation from Cerrena unicolor had no considerable effect on the resistance, capacitance, and impedance of L929 fibroblast cells, which was an indicator of no significant effect on its physiological processes. At the same time, those parameters exhibited a decrease in colon cancer cell viability. Following our previous and current studies on Cerrena unicolor, ex-LMS extracts can be safely used in anticancer therapy or chemoprevention with no significant harmful effects on normal cells.

Verification of the Protective Effects of Poplar Phenolic Compounds Against Poplar Anthracnose.

Poplar anthracnose caused by Colletotrichum gloeosporioides is one of the most important diseases widely distributed in poplar-growing areas in China, causing serious economic and ecological losses. In this study, three poplar species showed different resistance to poplar anthracnose: Populus × canadensis was resistant, Populus tomentosa was susceptible, and P. × beijingensis showed intermediate resistance. However, it remains uncertain whether phenolic compounds in poplar are involved in this resistance. Therefore, we determined the concentrations of phenolic compounds and their antifungal activity. Before and after the C. gloeosporioides inoculation, 20 phenolic compounds were detected in P. × canadensis and the number increased from 12 to 14 in P. × beijingensis but decreased from seven to four in P. tomentosa. Thus, phenolic compounds may be positively correlated with the degree of disease resistance. We selected seven phenolic compounds for further analysis, which varied considerably in content after inoculation with C. gloeosporioides. These seven compounds were salicin, arbutin, benzoic acid, salicylic acid, chlorogenic acid, ferulic acid, and naringenin, which helped poplar trees to limit the growth of C. gloeosporioides and differed in their antifungal effects, with phenolic acids having the strongest inhibitory effect. In addition, the optimal concentrations of different substances varied. We demonstrate that these phenolic compounds produced by poplar do play a certain role in the process of poplar resistance to anthracnose. These findings lay a foundation for future research into the antifungal mechanism of poplar trees and may be useful for enhancing the prevention and control of poplar anthracnose.

Application of the medical linear accelerator ELEKTA AXESSE in the study of sorption properties of impurities and absorption coefficients of medium and heavy chemical elements

In this article, the authors propose a new technique for measuring linear attenuation coefficients on the medical linear accelerator Elekta Axesse. Linear attenuation coefficients were obtained for four samples at different concentrations of substances at a gamma-ray energy of 6 MeV. A unified ionization chamber was used as a detector to register the transmitted gamma-ray beam through the samples under study. Linear absorption coefficients were obtained for elements B, C, O, S, Fe, Ba taking into account their concentration, as well as taking into account the different mass inclusion of paraffin in the samples under study, which is acyclic hydrocarbons CnH2n+2. The measurement results showed that taking into account certain components in impurities leads to relatively small, but quite noticeable differences in the determination of the total absorption coefficients. This is especially important to take into account for determining the concentration of light elements in samples. To determine the content of medium and heavy chemical elements, taking into account the content of light elements can be neglected. The use of a 6 MeV gamma-ray beam made it possible to reduce the errors in determining the absorption coefficients, since their dependence on energy in the region of applicable gamma-ray energies is not so great in comparison with the low-energy region, in which the shell effects for heavy elements will introduce significant contribution.

Multi-objective, rule and preference-based placement of quality sensors in water supply networks

To detect contaminant intrusion and, in general, to assess quality problems in their water distribution systems, water utilities need quality sensors that continuously measure, directly from the network, conductivity, PH, concentration of different substances, and other related parameters. Due to the nature of the objectives involved, the decision about where to place sensors in the network and the amount of them to be installed is a very challenging problem. In this investigation, we present a multi-objective approach to cast light on those decisions. Instead of a crisp solution, the multi-objective approach will provide a wide spectrum of solutions representing the best trade-off among all the decision criteria of the problem. This approach aims to integrate the practical experience of engineers into the decision-making process since, eventually, the solution will be selected among the Pareto front of solutions using the engineers' experience and the specific characteristics of their utility. To this end, the used algorithm adds agents based on both technical and user-preference rules on top of evolutionary search techniques to explore the decision space. The algorithm runs as a part of the Agent Swarm Optimization framework, a consolidated multi-objective software. Another novelty of this contribution is computational: the evaluation of the objective functions is executed directly in the MS SQL server and simulation data is never required to be loaded in their entirety. Without this important implementation detail, the solution for "large" water network models would not be affordable with the hardware typically used in desktop computers. To illustrate the solution process, a use case focused on a mid-size water supply network is addressed.

COMPARISON OF AS, HG AND TL HIGH-FREQUENCY ELECTRODELESS LAMPS FOR DETECTION OF ENVIRONMENTAL POLLUTION

Nowadays, there is an increasing necessity to determine the concentration of different substances in the environment in low concentrations, as more and more attention is paid to environmental pollution. This work is devoted to the comparison of main characteristics of high-frequency electrodeless light sources with different fillings for their use in high precision atomic absorption analysers.The spectral line intensities and profiles were studied in special design light sources, manufactured at Institute of Atomic Physics and Spectroscopy, with arsenic, mercury and thallium filling. Special attention is devoted to the UV lines of 193.7 nm and 197.2 nm of As, 276.8 nm, 377.6 nm of Tl and 253.7 nm of Hg spectral lines. The intensities and profiles were measured by means of a Fourier transform spectrometer.The deconvolution procedure was implemented to obtain the real form of emitted profiles for further analysis, since in the case of low –pressure or cold plasma, the instrumental function is on the same order that experimental profile and it has to be taken into account. The instrumental function can distort the real spectral line shape significantly, for example, it changes the width of the spectral line that leads to the uncertainties in the determination of such important plasma parameters like temperature. The instrumental function can conceal a detailed structure of the spectral line, like the dip in the line center caused by the self-absorption (self-reversal) and characterizing the radiation trapping.The integrated areas, values of self-absorption, and other parameters were obtained and compared for all fillings as a function of working regimes.

Gas recognition method based on the deep learning model of sensor array response map

It is important to detect and recognize the unknown gases or VOCs (Volatile Organic Compounds) in industrial safety issues. Electronic nose is a novel and portable method to detect the VOCs with high accuracy combined with sensor array and artificial intelligence algorithm. The results indicated that the multidimensional dynamic response signals of the sensor array can be viewed as the image form. Thus, a new method coupled dynamic response map with deep learning model (DLM) was proposed to improve the accuracy of the sensor array. The error-correcting output codes (ECOC) model with support vector machine (SVM) learners was applied to discriminate different VOCs. The results showed that the model with the data from the sensor array classified the VOCs more accurately than that with just single sensor. Further, a simple DLM network was trained to classify the VOCs with the accuracy of 92 %. Then the transferred VGG-19 model was further adapted to improve the generalization property of DLM with the accuracy of 90 %. Moreover, all sensors’ responses at certain time were normalized before building the model, which enhanced the prediction accuracy to 96 % for simple DLM and 94 % for transferred VGG-19. Finally, the concentrations of different substances were predicted with SVM and DLM. The results showed that the prediction error of SVM and DLM with multidimensional response map is lower that with the data from single sensor. Therefore, it is a feasible tool to detect VOCs with just one sensor module using the response map-DLM method proposed in this research.

Structure preserving computational technique for fractional order Schnakenberg model

The current article deals with the analysis and numerical solution of fractional order Schnakenberg (S-B) model. This model is a system of autocatalytic reactions by nature, which arises in many biological systems. This study is aiming at investigating the behavior of natural phenomena with a more realistic and practical approach. The solutions are obtained by applying the Grunwald–Letnikov (G–L) finite difference (FD) and the proposed G–L nonstandard finite difference (NSFD) computational schemes. The proposed formulation is explicit in nature, strongly structure preserving as well as it is independent of the time step size. One very important feature of our proposed scheme is that it preserves the positivity of the solution of continuous fractional order S-B model because the unknown variables involved in this system describe the chemical concentrations of different substances. The comparison of the proposed scheme with G–L FD method reflects the significance of the said method.

PL-008 Adaptation of skeletal muscle to aerobic exercise: specific transcriptome response to acute exercise and training

Objective Variety of processes including circadian rhythm and systemic factors affect expression of many genes in skeletal muscle during a day. Therefore, post-exercise gene expression depends on many factors: contractile activity per seas well as circadian rhythm, nerve activity, concentration of different substances in blood, feeding and fasting. In our study, we investigated specific for contractile activity changes in the transcriptome in untrained and trained (after an aerobic training programme) human skeletal muscle. The second goal was to examine effect of aerobic training on gene expression in muscle in basal state.
 Methods Seven untrained males performed the one-legged knee extension exercise (for 60 min) with the same relative intensity before and after a 2 month aerobic training programme (1 h/day, 5/week). Biopsy samples were taken at rest (basal state, 48 h after the previous exercise), 1 and 4 h after one-legged exercise from m. vastus lateralisof either leg. This approach allowed us to evaluate specific changes in the transcriptome associated with contractile activity. RNA­sequencing (84 samples in total; ~42 million reads/sample) was performed by HiSeq 2500 (Illumina).
 Results Two months aerobic training increased the aerobic capacity of the knee-extensor muscles (power at anaerobic threshold in incremental one-legged and cycling tests), the maximum rate of ADP-stimulated mitochondrial respiration in permeabilized muscle fibres and amounts of oxidative phosphorylation proteins. After one-legged exercise, expression of many genes was changed in exercised muscle (~1500) as well as in non-exercised muscle (~400). Pronounced changes in gene expression in non-exercised muscle may be associated with many factors, including circadian rhythm (result of GO analysis).
 To examine transcriptome changes specific for contractile activity, the difference in gene expression between legs was examined. In untrained muscle, one-legged exercise changed expression of ~1200 genes specific for contractile activity at each time point. Despite the same relative intensity of one-legged exercise, transcriptomic response in trained muscle was markedly lower (~300 genes) compare to untrained.
 We observed a strong overlap between transcriptomic responses (~250 genes) and particularly between enriched transcription factor binding sites in promoters of these genes in untrained and trained muscles. These sets of genes and transcription factors play the key role in adaptation of muscle to contractile activity independently on the level of muscular fitness.
 Surprisingly, 2 months aerobic training changed the expression of more than 1500 genes in basal state. Noteworthy, these genes demonstrated a small overlap (~200 genes) with genes related to specific response to acute exercise. Moreover, these genes were associated with significantly different biological processes than genes related to specific response to acute exercise.
 Conclusions Specific for contractile activity changes in the transcriptome in untrained and trained human skeletal muscle were revealed for the first time. After 2 month aerobic training, the specific transcriptome response to acute exercise become much less pronounced. A computational approach reveals common transcription factors important for adaptation of both untrained and trained muscle. We found out that adaptation of muscle to aerobic training associates not only with the transitory changes in gene expression after each exercise, but also with the marked changes in transcriptome in basal state.
 This work was supported by the Russian Science Foundation (14­15­00768).

Rapid in vitro assessment of hypersensitivity with whole blood leukocyte histamine release assay

Background. Clinical application of leukocyte histamine release assay (HRA) can be enhanced through the development of automated reversed-phase high-performance liquid chromatography with mass spectrometry (RP-HPLC-MS/MS) employing of whole blood (WB) samples. The purpose of this study was to evaluate the possibility to use WB-HRA technology for the in vitro diagnosis of hypersensitivity employing RP-HPLC-MS/MS. Methods. Method principle: heparinized whole blood samples after substitution of plasma with PIPES buffer («reconstituted» blood) are incubated at 37 °C with different concentrations of substances (allergens, drugs, chemicals, food etc.) suspected in relation to hypersensitivity reactions. Release of histamine is occured mainly from basophilic granulocytes depending on their sensitivity to stimulating substances (allergens etc.). The released histamine is subsequently direct determined in the supernatant using RP-HPLC-MS/MS technology. Heparinized whole blood (8 ml) was drawn from patients with sensitivity to D. pteronyssinus (D1), birch pollen (T3) and peach (F95) confirmed by case history and results of skin prick tests or detection of specific IgE. After removing plasma and substitute it with PIPES buffer aliquots of «reconstituted» blood were put into separate tubes (300-450 μl for macro-method) or to wells of U-shape 96-well micro-titer plate (150-200 μl for micro-method) already contained different concentrations (dilutions) of histamine standard, anti-IgE and allergenic extracts D1, T3, F95 including their chemically modified forms sD1 and sF95. After 1 h incubation at 37 °C tubes or plates were centrifuged and supernatants from each tube (macro-method) or well of the plate (micro-method) were directly analyzed for histamine content by RP-HPLC-MS/MS. Results. It is shown that the levels of histamine released from leukocytes of whole blood of patient sensitized to D. pteronyssinus upon stimulation with non-modified D1 extract are much higher than that of upon stimulation with modified sD1 that means that chemical modification of allergen leads to suppress of B-cell epitopes. It seems that this method is suitable for evaluation of hypersensitivity to allergen, as well as for detection of allergenicity of modified allergens (allergoids). We also found a significant reduction (in 60%) of histamine release from blood leukocytes upon stimulation with T3 extract in patient with sensitivity to birch pollen after allergen-specific immunotherapy (ASIT) in compare to the level of histamine before ASIT. These data indicate that our method of histamine release assay can be convenient as in vitro test for monitoring and evaluation of ASIT efficacy. It was also studied histamine release from blood basophils of patient with sensitivity to peach, confirmed by case history and detection in serum specific IgE. Incubation of patient's whole blood with peach extract (F95) resulted a histamine release at the level comparable to that of stimulated with anti-IgE. This high level of histamine is correlated with the level of allergen-specific serum IgE. Besides the incubation patient's blood with modified peach extract sF95 induced histamine release two times less than that of non-modified F95 indicating substantial reduction of sF95 allergenicity. So this methodology for detection of histamine released from leukocytes of whole blood may be successfully applied for diagnosis of food allergy employing of laboratory made allergenic extracts. Conclusion. Speed and simplicity of performance including the requirement of small quantities of blood makes the WB-HRA employing RP-HPLC-MS/MS a useful laboratory tool not only of scientific interest (detection of allergenicity of modified allergens, peptides etc.) but also of practical significance for evaluation the degree of sensitivity of patients to allergens (including those who received anti-allergic medication or ASIT), analysis of pathophysiological responses to drugs, chemicals and other compounds suspected for their adverse side effects.

The impacts of a Laki-like eruption on the present Swedish society

In this study, we analyse and discuss the possible impacts on the Swedish society of a volcanic eruption on Iceland, emitting ash particles and large quantities of sulphur dioxide. A scenario was developed, based on the historical Laki eruption of 1783–1784, to describe the content of a potential sulphur fog over time in Sweden. Due to its high complexity and the many uncertainties in the underpinning scientific data, the scenario was developed using a cross-disciplinary approach incorporating experts from different scientific fields. An analysis of the impacts of the hazard on human health, environment and technical equipment was then performed and, finally, representatives from national authorities assessed the overall societal challenges in responding to the consequences of a massive volcanic eruption. The analysis shows that it is the peak concentrations of sulphur dioxide and sulphuric acid rather than the longer periods of moderate concentrations that contribute most to the negative consequences for human health and environment. Altogether, three societal challenges were identified: the ability to compile and disseminate relevant information fast enough, to perform continuous measurements of concentrations of different substances in affected areas and to meet the large demand for medical care.

Photoreactors for Solving Problems of Environmental Pollution

Involvement of a huge amount of natural resources in the production sphere, synthesis of new materials and substances, and uncontrollable increase in the amount and volume of manufactured products engender a global problem of recycling and utilization of production and consumption wastes. The Earth atmosphere, hydrosphere and lithosphere are polluted. The atmosphere is a giant open reactor without walls in which hundreds of photochemical, dark, gas phase, liquid phase, homogeneous, and heterogeneous reactions take place with participation of all types of particles at various local temperatures and global pressure for different concentrations of substances and radiation intensities at different wavelengths. Hydroxyl radicals dominate in tropospheric chemistry as well as oxygen atoms and ozone dominate in stratospheric chemistry. Moreover, the photochemical processes proceed not only in surface waters, but also in the lithosphere in the upper soil layers [1, 2]. Anthropogenic effect on nature has already caused irreversible consequences. As a result of human activity, pollutants of many types are present in the environment. Chemistry of polluted urban atmospheres obligatory includes the photochemical processes. The typical pollutants presented in the photochemical (or Los Angeles) smog are ozone and nitrogen dioxide in combination with various organic compounds. The O3 and NO2 concentrations can be so high that ozone even smells, and large concentrations of aerosol particles cause the formation of grayish-brown haze in air. The pollution causes such consequences as destruction of materials, for example rubber, suppression of vegetation growth, reduction of the visibility range, and increase in the number of respiratory diseases. The most obvious consequence of the photochemical smog that manifests immediately is eye irritation caused by such compounds as formaldehyde, acrolein, and peroxyacetyl nitrate. The surface of solid aerosols and the inner volume of liquid-drop aerosols can also be the arena of various dark and photostimulated chemical reactions whose rates are largely determined by the catalytic properties of the surface and components forming particles. Many toxic impurities are detected in the aerosol composition, including compounds of heavy metals, carcinogenic polynuclear aromatic hydrocarbons, and polychlorinated compounds of different classes (pesticides, biphenyls, dibenzo-p-dioxins, and dibenzofurans). The largest amounts of these toxicants are contained in the smallest aerosol fractions capable of penetrating deep into the human respiratory tract and then into the blood system. Wide use of pesticides and herbicides in agriculture for the past few decades has significantly increased the number of persistent organic compounds in natural waters and soils [3–5]. For these reasons, the necessity arose to revise old technologies and to develop new ones aimed at resource saving and environmental protection. Experimental

Moisture absorption and dimensional stability of poplar wood impregnated with sucrose and sodium chloride

This paper deals with the effect of vacuum-pressure impregnation of Poplar wood (Populus alba) by aqueous solutions of sucrose and sodium chloride on its physical properties. Groups of samples with different concentrations of substances in the aqueous solution were compared within each other and also with a reference (non-impregnated) group. The specimens from all groups were tested for density, moisture absorption and dimensional stability. The obtained data were statistically analysed and compared each other. The most satisfying final properties were achieved in impregnation of sucrose with concentration of 6,25 g/100 ml H2O. The retention was 31 kg m-3 (WPG around 8 %). The values of ASE (anti-swelling efficiency) reached to 36 % and MEE (moisture exclusion efficiency) was reduced by 33 %.

Kinetic Proofreading at Single Molecular Level: Aminoacylation of tRNAIle and the Role of Water as an Editor

Proofreading/editing in protein synthesis is essential for accurate translation of information from the genetic code. In this article we present a theoretical investigation of efficiency of a kinetic proofreading mechanism that employs hydrolysis of the wrong substrate as the discriminatory step in enzyme catalytic reactions. We consider aminoacylation of tRNAIle which is a crucial step in protein synthesis and for which experimental results are now available. We present an augmented kinetic scheme and then employ methods of stochastic simulation algorithm to obtain time dependent concentrations of different substances involved in the reaction and their rates of formation. We obtain the rates of product formation and ATP hydrolysis for both correct and wrong substrates (isoleucine and valine in our case, respectively), in single molecular enzyme as well as ensemble enzyme kinetics. The present theoretical scheme correctly reproduces (i) the amplitude of the discrimination factor in the overall rates between isoleucine and valine which is obtained as (1.8×102).(4.33×102) = 7.8×104, (ii) the rates of ATP hydrolysis for both Ile and Val at different substrate concentrations in the aminoacylation of tRNAIle. The present study shows a non-michaelis type dependence of rate of reaction on tRNAIle concentration in case of valine. The overall editing in steady state is found to be independent of amino acid concentration. Interestingly, the computed ATP hydrolysis rate for valine at high substrate concentration is same as the rate of formation of Ile-tRNAIle whereas at intermediate substrate concentration the ATP hydrolysis rate is relatively low. We find that the presence of additional editing domain in class I editing enzyme makes the kinetic proofreading more efficient through enhanced hydrolysis of wrong product at the editing CP1 domain.

Effects of pollution on macroinvertebrates and water quality bio-assessment

Many large rivers in China have an inflow of contaminated water. Water pollution caused by urban sewage and agriculture, and occasionally pollution events from industries have become a significant stress on aquatic ecology. Pollution affects the biodiversity of the aquatic community and the species composition changes from natural species to tolerant species. The species composition of aquatic animals may reflect water pollution level. Extremely non-uniform distributions of functional feeding groups occurred as a result of high nutrient levels. A combination of chemical and biological methods constitutes the best approach for biological monitoring studies that measure water quality. Macroinvertebrates were used as bio-assessment indicator to determine the environmental quality of given water body. In this study, samples of water and macroinvertebrates were taken from several dozen sites in 14 rivers in China with different pollution levels, including the Yangtze, East, Weihe, Songhua, Yongding, and Panlong rivers. Macroinvertebrates were identified to genus or family level. Water samples were classified into different water quality grades according to the concentration of different substances. Five biological indices: taxa richness (S), density (D), total BMWQ score (t-BMWQ), average BMWQ score (a-BMWQ), and the family biotic index (FBI) were used for biological assessment of water quality. Analyzing macroinvertebrates’ occurrence in different water quality levels, taxa-specific indicators, which are defined as the taxa of macroinvertebrates that live in a certain water quality level but do not exist in other water quality levels were proposed for water quality bio-assessment. Leptophlebiidae, Siphlonuridae, Arctopsychidae, Perlidae, and Antocha sp. are the taxa-specific indicators for very good or good water quality; Chironomidae, Lymnaeidae, Tubifex sp., Limnodrilus sp., Limnoperna lacustris, Corbicula sp., Macrobrachium sp., Planorbidae, Glossiphoniidae, and Branchiura sp. are the taxa-specific indicators for very poor water quality; and Psychomyiidae and Hydroptilidae are the taxa-specific indicators for moderate water quality.

Evaluation of the Charm maximum residue limit β-lactam and tetracycline test for the detection of antibiotics in ewe and goat milk

The Charm maximum residue limit β-lactam and tetracycline test (Charm MRL BLTET; Charm Sciences Inc., Lawrence, MA) is an immunoreceptor assay utilizing Rapid One-Step Assay lateral flow technology that detects β-lactam or tetracycline drugs in raw commingled cow milk at or below European Union maximum residue levels (EU-MRL). The Charm MRL BLTET test procedure was recently modified (dilution in buffer and longer incubation) by the manufacturers to be used with raw ewe and goat milk. To assess the Charm MRL BLTET test for the detection of β-lactams and tetracyclines in milk of small ruminants, an evaluation study was performed at Instituto de Ciencia y Tecnologia Animal of Universitat Politècnica de València (Spain). The test specificity and detection capability (CCβ) were studied following Commission Decision 2002/657/EC. Specificity results obtained in this study were optimal for individual milk free of antimicrobials from ewes (99.2% for β-lactams and 100% for tetracyclines) and goats (97.9% for β-lactams and 100% for tetracyclines) along the entire lactation period regardless of whether the results were visually or instrumentally interpreted. Moreover, no positive results were obtained when a relatively high concentration of different substances belonging to antimicrobial families other than β-lactams and tetracyclines were present in ewe and goat milk. For both types of milk, the CCβ calculated was lower or equal to EU-MRL for amoxicillin (4µg/kg), ampicillin (4µg/kg), benzylpenicillin (≤2µg/kg), dicloxacillin (30µg/kg), oxacillin (30µg/kg), cefacetrile (≤63µg/kg), cefalonium (≤10µg/kg), cefapirin (≤30µg/kg), desacetylcefapirin (≤30µg/kg), cefazolin (≤25µg/kg), cefoperazone (≤25µg/kg), cefquinome (20µg/kg), ceftiofur (≤50µg/kg), desfuroylceftiofur (≤50µg/kg), and cephalexin (≤50µg/kg). However, this test could neither detect cloxacillin nor nafcillin at or below EU-MRL (CCβ >30µg/kg). The CCβ for tetracyclines was also lower than EU-MRL for chlortetracycline (ewe milk: ≤50µg/kg; goat milk: 75µg/kg), oxytetracycline (≤50µg/kg), and tetracycline (≤50µg/kg). Regarding the 4-epimers of these tetracyclines only 4-epioxytetracycline was detected by the Charm MRL BLTET test below EU-MRL (ewe milk: 75µg/kg; goat milk: ≤50µg/kg). Acidiol had no effect on the performance of the test. The Charm MRL BLTET test could be used routinely with adapted test procedure for the fast screening of ewe and goat milk.